When a person is operating a keyboard or other computer input device, positioning of the wrists in an unsupported manner for long periods of time may lead to repetitive stress injuries such as carpal tunnel syndrome. To lessen these types of injuries, it is common to use wrist rest assemblies along the front edge of a device operated by a person's hands or fingers, such as in front of a computer keyboard, computer mouse, or other input device. It has been suggested that the use of such wrist rest assemblies can limit or eliminate the damage that is sometimes caused by prolonged, repetitive use of these input devices.
One simple type of wrist rest assembly is comprised of an elongated rectangular layer of cushioning material that may be used alone or may be mounted on a base. Wrist rests of this type are typically placed on a work surface directly in front of a keyboard so that the user's wrists can rest on the layer of cushioning material when typing or when resting during a typing session. Although these wrist rest assemblies may provide support for the user's wrists and can help to relieve some stress on the wrists of the user, these assemblies are not height or tilt adjustable to accommodate the needs of different users.
To address the problems related to nonadjustable wrist rest assemblies, several different types of wrist rest assemblies have been provided that allow the user to adjust either the height, the inclination, or both the height and inclination of the wrist rest. One example of a wrist rest assembly having a pad that may be adjusted vertically is described in U.S. Pat. No. 5,547,154 (Kirchhoff et al.), which is commonly owned by the assignee of the present invention. This wrist rest assembly comprises an elongate base assembly on which is supported an elongate pad of cushioning material. The base assembly has a top portion supporting the pad, a bottom portion adapted to be supported on a horizontal surface, and a structure that allows the top portion to be supported on the bottom portion, where the top surface of the pad can be at two different distances above the horizontal surface by switching the ends of the top portion with respect to the ends of the bottom portion. Although this type of device is useful for adjusting a wrist rest to two different vertical heights, it does not allow for any inclination adjustment, which is sometimes also desirable to accommodate each particular user's comfort, needs, and preferences.
Different methods have been proposed for adjusting both the height and inclination of wrist rest assemblies. For one example, U.S. Pat. No. 5,507,458 (Campbell et al.) describes an wrist rest assembly that is adjustable for both height and inclination. This wrist rest comprises a platform having a top surface that is provided with padding, a bottom surface, and two ends. A cup extends from each of the ends, where each cup has grooves on its outer perimeter to rotatably receive a cylinder having grooves on its inner perimeter so that as the cylinder is rotated it moves up or down the cup to change the height of the platform. This assembly also has a means for adjusting the inclination of the wrist rest through the cooperative adjustment of a bolt that extends through a convex shaped cup having a longitudinal slot. Other examples of adjustable wrist rest assemblies include those described in U.S. Pat. No 5,374,018 (Daneshvar), which uses one or more inflatable balloons to set the height and angulation of a wrist support pad, and U.S. Pat. No. 5,375,800 (Wilcox et al.), which uses an eccentric cam for elevation adjustment and a hinged arm for angulation adjustment of a wrist rest. Each of these wrist rest assemblies comprise multiple components that must be precisely manufactured and properly assembled and adjusted before they can be provided to a user.
Thus, the general use of adjustable wrist rest devices is well known. However, there is a continuing need for simple, cost effective adjustable wrist rest assemblies for those using computer input devices such as keyboards.